In New York City last year, 141 were struck by subway trains, and 55 were killed. There have been several recent high-profile deaths on the tracks, including one that made the cover of the NY Post. Falling (or being pushed) in front of a train is a classic nightmare scenario. So what should we do to prevent it? Well... something cheap, if anything.

A common refrain after hearing about someone dying on the tracks: "Why don't they build doors on the platforms?" Other cities have sliding doors that open when trains arrive, thereby keeping everyone safely on the platform. Yesterday, the M.T.A. said the cost of building such doors throughout the system would be $1 billion, conservatively. (The M.T.A. also said the 2nd Avenue Subway line would be finished years ago, so you can safely inflate that number upwards.)

The WSJ calculates the risk of being hit by a train during your subway trip as one in 11.8 million. The risk is quite low. Nine of the top ten causes of death in New York City are from either disease, or natural causes. The only exception is "Unintentional injuries," which ranks sixth, just behind diabetes. The top ten causes of injury-related death do not include being hit by subway cars. The top five: unintentional poisoning, unintentional falls, homicide by firearm, unintentional pedestrian injury, and suicide by hanging. (Unintentional death by motor vehicles is sixth, but subway deaths would account for only a small fraction of those.)

So, rationally, if we're going to spend public money to help reduce the risk of death, it would make sense to first tackle public health; since diabetes is more deadly than injuries, I hope that everyone calling for subway doors is also a big supporter of Bloomberg's big soda ban. Even if you want to invest to prevent injury deaths specifically, subways are not the best place to do it. Hell, considering the fatality rates of unintentional falls, a billion dollars invested in anti-slip bathtub mats would probably prevent more deaths than an entire system's worth of doors on subway platforms.

As Jared Diamond points out, it makes much more sense to address common risks (obese citizens, smoking, unsafe sex, guns, household accidents, cars) than uncommon risks (being pushed onto the subway tracks by a raving madman). America, of course, tends to go in for the "Bankrupt ourselves in a largely futile effort to prevent spectacular and spectacularly rare risks like terrorism" strategy, generally. But in any arena with limited resources/ budgets, the resources should to where they'll have the greatest impact. (This common-sense principle is already widely accepted in the do-gooder world.) Otherwise, you're wasting at least part of them. And by wasting that part of them, you're failing to prevent as many deaths as you could. By being seduced by sensational incidents, we make poor resource allocations, which indirectly lead to more preventable deaths. Great.